1. Field of the Invention
The field of the invention is that identified in the Abstract.
2. Description of the Prior Art
The typical methods of handling the solids removed in the treatment of wastewaters such as domestic sewage and the like consist of collecting the solids from the various treatment units as a sludge; this sludge is commonly of 95-99% water content; and subjecting this sludge to one or more of the following treatments:
1. Transporting the sludge to a digester which is an enclosed volume in which the collected sludge undergoes biological digestion processed under anaerobic conditions for a period commonly varying from twenty to thirty days, after which the sludge (now typically reduced in organic content an additional fifty percent by the digester action) is removed either in tank trucks by deposition on lands available for such purposes or is pumped to drying beds for dewatering by evaporation and leaching. In the latter case, the dried sludge, after perhaps an additional thirty days of drying, is removed by vehicles to a land disposal site for that purpose.
2. Transporting the sludge to an incinerator where it is burned and the residual ash deposited in a disposal site available for that purpose.
3. Transporting the sludge to a reactor where heat, air and high pressure conditions transform part of it into relatively sterile matter suitable for use as a soil supplement or for disposal in sanitary landfills.
4. Transporting the sludge directly to sand beds for drying with subsequent handling as in case 1 above.
All the approaches described above handle sludge, which is primarily water rather than relatively dry, solid matter. All of the above-listed processes either require considerable processing time (as in the case of the digester process or in the sand bed drying process) or less considerably costly investment in sophisticated equipment with high capital and maintenance costs.
5. In cases of ocean discharge, costly piping is required which extends for miles out into the ocean.
6. Most water discharges are unsuitable for irrigation and other domestic uses.
Prior art patents are U.S. Pat. Nos.: 681,884; 1,945,051; 2,209,613; 2,222,310, 3,397,140; 2,279,603; 3,236,766; 3,256,179; 3,576,738; 3,361,779; 3,462,275; 3,613,893; 3,622,508; 3,640,820; 3,725,264; 3,700,565; 3,864,251; and Lindsley, Popular Science, Oct. 1970, p. 102, 103 and 138.
The herein system may be used in conjunction with any or all of the above treatment processes. The system which is described herein may be embodied as a treatment process independent of any of the above-mentioned typical wastewater treatment processes, even though it is also simply integratable into a treatment system which does use one or more of the above-mentioned typical treatment processes. Economics indicate the independent method is the most desirable way to go.